Ship with node 12

Closes #1894

Author: nhooyr

ci/images/centos7/Dockerfile

@@ -1,9 +1,10 @@
 FROM centos:7
 
+ARG NODE_VERSION=v12.9.1
 RUN ARCH="$(uname -m | sed 's/86_64/64/; s/aarch64/arm64/')" && \
-    curl -fsSL "https://nodejs.org/dist/v14.4.0/node-v14.4.0-linux-$ARCH.tar.xz" | tar -C /usr/local -xJ && \
-    mv /usr/local/node-v14.4.0-linux-$ARCH /usr/local/node-v14.4.0
-ENV PATH=/usr/local/node-v14.4.0/bin:$PATH
+    curl -fsSL "https://nodejs.org/dist/$NODE_VERSION/node-$NODE_VERSION-linux-$ARCH.tar.xz" | tar -C /usr/local -xJ && \
+    mv "/usr/local/node-$NODE_VERSION-linux-$ARCH" "/usr/local/node-$NODE_VERSION"
+ENV PATH=/usr/local/node-$NODE_VERSION/bin:$PATH
 RUN npm install -g yarn
 
 RUN yum groupinstall -y 'Development Tools'

ci/images/debian8/Dockerfile

@@ -6,7 +6,7 @@ RUN apt-get update
 RUN apt-get install -y curl gnupg
 
 # Installs node.
-RUN curl -fsSL https://deb.nodesource.com/setup_14.x | bash - && \
+RUN curl -fsSL https://deb.nodesource.com/setup_12.x | bash - && \
     apt-get install -y nodejs
 
 # Installs yarn.

ci/steps/release-packages.sh

@@ -5,8 +5,8 @@ main() {
   cd "$(dirname "$0")/../.."
 
   if [[ $OSTYPE == darwin* ]]; then
-    curl -L https://nodejs.org/dist/v14.4.0/node-v14.4.0-darwin-x64.tar.gz | tar -xz
-    PATH="$PWD/node-v14.4.0-darwin-x64/bin:$PATH"
+    curl -L "https://nodejs.org/dist/$NODE_VERSION/node-$NODE_VERSION-darwin-x64.tar.gz" | tar -xz
+    PATH="$PWD/node-$NODE_VERSION-darwin-x64/bin:$PATH"
   fi
 
   # https://github.com/actions/upload-artifact/issues/38